1. Field of the Invention
This invention relates to an epoxy bonded laminate door beam or impact beam assembly for a vehicle door and, in particular, to a stackable door beam having a base metal stamping and which is provided with one or more slidable and stackable elongated plastic elements thereon to vary the strength of the beam from car line to car line. The metal stamping is of an inverted U-shaped cross section and the plastic elements are each of generally M-shaped configuration and are manufactured using conventional forming techniques.
2. Description of the Prior Art
Impact protection is of prime importance to the automotive industry. Independent beams have been employed in a manner to prevent deep penetration of an impacting vehicle into the passenger space of an impacted vehicle. Such independent beams have taken various forms. One form is that of a convoluted strip of sheet steel spanning a generally mid-section of the door as well as bisecting the interior door space, with the beam being rigidly attached such as by welding to the opposite portions of the door frame. Since impact forces may be quite high, the beams have been generally made of moderate gauge high-strength steel.
Other beams include structural steel members which extend between the fore and aft vertically extending walls of the vehicle door. In the past, these structural members have been stamped from sheet metal into various cross-sectional configurations, most commonly a hat-shaped cross section. Straight tubular beams with various end attachments are also used for these structural steel members.
However, certain drawbacks surround the use of such known beams including the obstruction of space within the interior of the door to thereby hinder the location of a variety of mechanism and wiring to be installed within the door. In addition, the weight of the impact beams have adversely increased the overall weight of the vehicle.
Furthermore, Federal Vehicle Safety Standards specify that side door impact beams must meet certain load or energy absorbing criteria for a specified lateral displacement of the door in response to a vehicle being subjected to a side impact. While known side door impact beam assemblies used in vehicles produced in the United States of America have been satisfactory in use, and have meet the Federal Vehicle Safety Standards, there is a continuing effort to reduce the mass and/or cost of these assemblies and the tooling used in making same without sacrificing protection or energy-absorption of these side impact beam assemblies.
Accordingly, automobile manufacturers are desirous of providing enhanced impact resistance by an impact beam which offers greater strength and flexibility and economical advantages.
The present invention relates to a stackable door beam or impact beam which consists of a base stamping made out of metal and having one or more stackable plastic elements superimposed on one another and onto the base metal stamping, with an adhesive layer such as epoxy resin interposed between adjacent pieces.
The vehicle door intrusion beam of the present invention includes a longitudinal door beam metal stamping having first and second ends and a length therebetween, with the metal stamping having a generally inverted U-shaped cross section having a base with a pair of legs, with the base at the center thereof having a longitudinally extending recess throughout the length of the metal stamping and with the legs being directed downwardly and outwardly away from the recess and having the ends of the legs curved throughout the length of the door beam metal stamping. One or more slidable and stackable elongated plastic elements are superimposed one on top of the other and on the longitudinal door beam metal stamping, with each of the slidable and stackable elongated plastic elements having a generally M-shaped cross section which is symmetrical about the center thereof and including a base and a pair of legs, with the center portion of the base of each plastic element being depressed to form a longitudinally extending channel. The channel of the first plastic element closest to the door beam metal stamping is received and nested in the longitudinally extending recess provided in the door beam metal stamping, with the channel of each of the plastic elements after the first mentioned plastic element being received in the preceding channel of the adjacent plastic element. The pair of legs of each plastic element extend downwardly and away from its respective channel, with portions of the legs of the plastic channel engaging the outer surfaces of the legs provided on the door beam metal stamping or on the legs of the preceding plastic element.
With such a construction, the longitudinal door beam metal stamping has a length equal to or greater than the length of the slidable and stackable elongated plastic element. Layers of structural adhesives such as an epoxy resin are interposed between the metal stamping and the first mentioned plastic element and between the surfaces of abutting adjacent plastic elements throughout the length thereof which bonds and secures the plastic elements and the metal stamping together as an integrated door intrusion beam which can be mounted in the interior well of the vehicle door.
Another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein each of the plastic elements are slidable and adjusted lengthwise on the metal stamping to provide the required yield strength of the door intrusion beam.
Still another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein one of the layers of a structural adhesive is provided between the channel of the first plastic element and the longitudinally extending recess of the metal stamping and between the surfaces of the legs of the first plastic element and the legs of the metal stamping.
A further feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein metal end brackets are provided on the first and second ends of the metal stamping for mounting the intrusion beam in the interior weld of the door of the vehicle.
A still further feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the end brackets have means for securing the intrusion beams to the door.
Another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the end brackets are integrally formed with the metal stamping from a single piece of metal material.
Still another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the plurality of slidable and stackable plastic elements include two or more elements which are slidably positioned and located relative to the metal stamping depending on the required yield strength of the door intrusion beam.
A further feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein there are three slidable and stackable plastic elements of varying lengths positioned and located on the metal stamping depending on the yield strength of the door intrusion beam.
A still further feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the first plastic element has a length equal to or less than the length of the metal stamping, while the second plastic element has a length equal to three-fourths the length of the metal stamping and while the third plastic element has a length equal to one-half the length of the metal stamping.
Another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the second and third plastic elements may be placed at either n end of the metal stamping or at any position between the ends thereof.
Still another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the structural adhesive is an epoxy bond material which may be either a heat bonded glue or a heat sensitive glue.
A still another feature of the present invention is to provide a door intrusion beam of the aforementioned type wherein the metal material is initially rolled, then flattened on the ends and finally stamped to the requisite configuration and the plastic elements are rolled by moving plastic strip material through rolled forming equipment and thereafter cutting the formed plastic elements to length.